The Call, Column 87 – That Big Clock in the Sky

4 01 2018

(December 31, 2017)

The Urban Farmer

That Big Clock in the Sky

Imagine that you’re sitting alone in a kitchen with a leaky faucet. The water drips, drips, drip, in a steady and predictable rhythm, and it’s basically the only sound you hear.

There is a certain type of person – myself proudly included – who would slowly start tapping their fingers together with the dripping. Do you know what I mean? In this situation, I always find myself absentmindedly tapping my fingers, or hitting my knee, or clicking my tongue, aligning my own noise to that of each drip of water; or, to the clicking of the turn signal in my car, or the backup signal of a garbage truck, or any similar sound.

Right now, you’re probably wondering what I’m getting at. I know this was a weird lead in, but let me try to peak your interest. This type of activity is a good example of what we in the technical world call “clock synchronization”. A periodic ticking – whether the drumming of your fingers, or the second-hand on a walk clock, or even the digital clock signal inside basically every computer and electronic device you’ve encountered – is made to align with the rhythmic ticking of some other, “master clock”.

A human making noise in sync with a leaky faucet is probably just some psychological compulsion or whatever. But when it’s done in the technological world, it’s with an important purpose. Electronic devices synchronize their internal clocks to some master clock, whether over the internet, or a closed-circuit interconnection, or a radio signal, or something like that, because their behavior needs to be driven by some “standard” time-base. Your MP3 player needs to play Ke$ha’s, “TiK ToK”, at the correct speed, so it actually fits in the 215 seconds that are expected. Your phone needs to know the time of day, every day, so it can switch to night/day mode, monitor for notifications, and all sorts of other behavior. And your favorite clock – whether the digital alarm clock by your bedside, which uses the regular pulses that come from the electric grid to keep time, or the analog wall clock in your kitchen, which relies on finely-tuned gears and regular human adjustment – simply needs to display and maintain the actual time of day (and oftentimes the date), because the daily rotation of the Earth on its own axis, and its yearly rotation around the Sun, are the basic time-base for human society.

And with that last example, we’ve finally arrived at the main point of today’s column: the position of the Sun relative to the Earth

And it is in this last example that we’ve finally arrived at the main point of today’s column: the Sun is Earth’s “master clock”, and its position (relative to the Earth) is the steady, predictable ticking to which basically everything on the surface of our planet aligns itself.

I can’t overstate how cool that fact is. This “solar clock” was essential in the development of basically everything on the surface of our planet.

This was primarily due to energy. In the course of one 24-hour “day” – that is, one full rotation of the Earth its own axis – a location’s “daytime” in when the Earth is rotated so it has a direct line of sight to the Sun, and “nighttime” is when it does not. This correlates to solar energy delivery, with a lot of it being dumped into that area during the day, and very little at night, which is why day is generally warmer than night.

And over the course of one 365-day “year” – one full rotation of the Earth around the Sun – a location’s “summer” is when the Earth is tilted towards the Sun for the most time each day relative to other days in the year, and its “winter” is when the Earth is tilted away from the Sun for the most time each day. This also correlates to solar energy delivery, with the most energy being dumped into that area during the summer, and the least during the winter – hence why summer is generally warmer, and winter generally colder.

This regular variation in the amount of solar energy that hits Earth, over the course of one day and one year, is responsible for so much of the behavior we see in Earth’s environment. The temperature of the air, water, and soil is, of course, driven by the ebbs and flows of solar energy. The same is true of air pressure, humidity, and even the amounts of certain other gases in the atmosphere.

The entire hydrological cycle is driven by solar energy, as we’ve discussed in past columns. Evaporation is faster with higher environmental temperatures and more direct sunlight; condensation (the water turning into clouds) requires lower temperatures; the type of precipitation (snow versus rain versus hair) that forms, and the amount that falls, also has to do with atmospheric conditions like pressure and temperature.

To varying degrees, every biogeochemical cycle is driven by the delivery of solar energy, and therefore ebbs and flows over the day and the year. These, and all of the other examples above, I will call the “passive solar clock”. These are effects in our environment (and even, in some cases, in biological organisms) that happen because of the amount of solar energy reaching Earth, and change based on the periodic changes in that energy.

I call this the “passive” clock to distinguish it from (what I think is) the much more interesting “active solar clock”: information about where the Earth is in its daily and yearly rotation, based on the Sun’s position in the sky and other indicators. Many biological organisms are able to use knowledge of this active solar clock to maintain their own time-base, synchronized with the Sun, and shape their characteristics and behavior accordingly.

If what we’ve discussed today can be described as the cosmological, physical, and chemical aspects of the Sun as Earth’s master clock, then next week’s column will be the biological and…let’s say…“computational” aspects. That is largely more interesting in my opinion, and can shed a lot of light (see what I did there?) on the way things behave in our environment. I can’t wait!

My column appears every other Sunday in The Woonsocket Call (also in areas where The Pawtucket Times is available). The above article is the property of The Woonsocket Call and The Pawtucket Times, and is reprinted here with permission from these publications. These are excellent newspapers, covering important local news topics with voices out of our own communities, and skillfully addressing statewide and national news. Click these links to subscribe to The Woonsocket Call or to The Pawtucket Times. To subscribe to the online editions, click here for The Call and here for The Times. They can also be found on Twitter, @WoonsocketCall and @Pawtuckettimes.

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